Methods previously used for performing gammarid bioassays and several important life-cycle requirements are reviewed. The discussion is largely based on methodology for the amphipods Gammarus fasciatus, Gammarus lacustris, and Gammarus pseudolimnaeus, but additional evidence, gathered from other selected freshwater crustacean tests, is included. The survival rate, acclimation period, test chamber size, and age of the amphipods are discussed for short-term tests. The survival rate, isolation versus nonisolation of gravid females, sex ratios during the reproductive period, and test duration are considered for the long-term tests. Primary emphasis should be placed on flow-through methods. The particular problem under investigation will ultimately determine the methods and species required. At present, the choice of species may be G. lacustris because a higher success in laboratory culturing has been achieved for this species, and more information is available about its life-cycle requirements.